Rich Felker
c68de0be2f
this change is needed to fix a race condition and ensure that it's possible to unlock and destroy or unmap the mutex as soon as pthread_mutex_lock succeeds. POSIX explicitly gives such an example in the rationale and requires an implementation to allow such usage.
25 lines
621 B
C
25 lines
621 B
C
#include "pthread_impl.h"
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int pthread_mutex_timedlock(pthread_mutex_t *m, const struct timespec *at)
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{
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int r, t;
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if (m->_m_type == PTHREAD_MUTEX_NORMAL && !a_cas(&m->_m_lock, 0, EBUSY))
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return 0;
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while ((r=pthread_mutex_trylock(m)) == EBUSY) {
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if (!(r=m->_m_lock) || (r&0x40000000)) continue;
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if ((m->_m_type&3) == PTHREAD_MUTEX_ERRORCHECK
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&& (r&0x1fffffff) == pthread_self()->tid)
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return EDEADLK;
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a_inc(&m->_m_waiters);
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t = r | 0x80000000;
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a_cas(&m->_m_lock, r, t);
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r = __timedwait(&m->_m_lock, t, CLOCK_REALTIME, at, 0);
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a_dec(&m->_m_waiters);
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if (r && r != EINTR) break;
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}
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return r;
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}
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